Closure plug



Dec. 22, 1953 c. P. YARNALL 2,663,451

cLosURE PLUG Filed Oct. 10, 1951 Patented Dec. 22, 1'953 UNITED STATES PATENT, GFFICE' 2,663,451 I v 5 j CLOSURE PLUG Chandler P. Yarnall, Merchantville, N. J. A

Application October 10, 1951, Serial No. 250,743-

(ol. '22o-24) 2 Claims.

(Granted under Title 3 sec. l

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to closure plugs and more particularly to closure plugs which are capable of effecting a positive moistureand vaporproof seal. More specically, the present invention is concerned with iiexible rubber closure plugs for ports, breather openings, tubes and similar orices in engines and like equipment to effect a positive and lasting seal against the entrance of moisture or the leakage ofpreserving compound or oil within such equipmenty andl to remain in effective sealing position without damaging or distorting the port or opening until the removal thereof is desired.

Heretofore, closure plugs intended for such purposes have been made of wood, metal, or plastics, or various combinations thereof but have been found to be unsuitable for several reasons. A positive sealing effect was not obtained in many instances with the result that moisture entered the interior of the equipment or the preserving compound or oil escaped therefrom with the result that parts rusted or oxidized. This was especially noted Whenever thecontour of the port or opening was not perfectly regular and the plug could not adapt itself sufficiently to assume that contour to prevent leakage. In many cases, the plugs were used with openings which had been carefully machined and finished to extremely close allowances and tolerances and have caused distortion or other damage thereto because of the poor fit therein. Another consequence of such poor ts developed when the equipment was subjected to the jolting and jouncing in transit when the plugs would fall completely out of the openings to permit foreign or other extraneous matter to enter therein whereby close inspection'and perhaps repair of the equipment would be required after transit. It has also been determined that the closure plugs pres'- ently in use are unsuitable for manyof the operations to which such equipment is subjected, such as sand blast cleaning, forexample, wherein a rapid erosion and wearing ofthe closure plug was noted. As a result, the plugs now in use have not 'been found to be completely satisfactory and their performance leaves much to be desired.

It is a purposeof the present invention to provide closure plugs for ports and openings which will be capable of effecting a positive and lasting moistureand vaporproof seal.

5,i U. S. Code (1952),

It is a further purpose of the present invention to provide closure plugs for ,ports or openings which can be easily inserted therein and easily removed therefrom whenv desired.

It is a still further purpose of the present invention to provide closure plugs for ports or openings which williit firmly in position without distorting or otherwise damaging the port or opening and which Will remain in such position dur-` ing the jolting and jouncing incident to transit.

Another purpose of the present invention isv to provide closure plugs which are sufficiently flexible and yieldable` to conform to ports and openings which are not' perfectly regular.

Still another puropse of the present invention` specification and the accompanying drawing,

wherein I have described and illustrated a preferred embodiment ofvmy invention but it is to be understood that my invention and inventive concept is not to be construed as limited to the specinc constructions described or shown therein, except as determined by the scope of the appended claims. n

With reference to the accompanying drawmg:

Figure 1 is aplan view of a closure plug of the present invention. Y Y

Figure 2 is a cross-sectional view of the closure Yplug of the present invention, taken on the line 2--2 of Figurel.

Figure 3 is a cross-sectional view of a modification of the closure plug of the present invention taken on a line similar'A to that used for Figure 2.

Referring to the accompanying ydrawing Wherein is set forth preferred embodiments of the present invention, the closure plug I0 possesses a shallow bowl or cup-like configuration and comprises a relatively thin circular base or bottom Wall l2 and a circumferential side Wall I4 ex' tending longitudinally upwardly therefrom. This side wall I4' is conically flaredoutwardly from 3 or less depending upon the necessities of the particular circumstances.

A series of longitudinally spaced circumferential flanges I6 are formed on the exterior of the side wall in the form of tapering fins extending outwardly therefrom. Three of such fins have been illustrated but it is to be appreciated that more or less may be employed, as desired or necessary. The fins I6 terminate in sharply defined edge portions I8 which, due to their relative acuteness and thinness have considerable ilexi? bility and yieldability under applied pressure.

A radially extending annular flange or lip is sure is applied thereto during the seating of the formed on the upper portion of the side Wall I4 and possesses a flat underhead portion 22 Awhich forms the plug seat for a purpose to be described hereinafter.

A cored-out recess 26 is thus formed within the side Walls I4 and the annular` flange '29 whereby considerable flexibility is given to the thin circular base I2 and to the side Walls I4. A removing tab or stub 28 is provided substantially at the center of the upper surface of the circular base I2 and extends longitudinally upwardly suiiciently to be gripped Vby the fingers or by any appropriate tool or device whereby the'plug It may be inserted into or removed from the opening or port. Such removing tab 28 has been shown as having an oval transverse cross-section but it is apparent that any other conformation may be usedprovided sufficient gripping surface is presented. Y

The closure plug I0 is intended to be used in conjunction with engines or similar equipment having a port or opening such as, for example, orifice 30 having internal walls 32 and an outer surface 34 adjacent the orifice 30 so that the minimum diameter of the extremities or tip i3 of the lowermost fln I6 is substantially equal to or preferably slightly greater than the diameter of the orifice 3G, The closure plugs I0 could be made up in a series or set of successively increasing diameters whereby a proper selection could be made of the desired closure plug. However, where the plugs are to be usedrwith carefully machined and nished parts, it may be advisable to make the plugs specially therefor.

When the closure plug, Figure 2, is inserted into the orifice 30, it entersrvery easily therein with the sharply defined edges of the fins IE yielding slightly to permit such entry. Simultaneously when inserting pressure is applied thereto on said removing tab 28, which in turn is transmitted to the circular base or diaphragm I2, this circular base no longer remains straight as illustrated, Figure 2, but assumes a convex nature. The potential tendency ofthe distorted convex circular base I2 resiliently acts upon the iins as they have slightly yielded upon entry heretofore described. In yielding thereof these line contact concentric fins I6 offer the maximum resistance to removal and the most eflcient seal. The direct result is that the closure plug will not fall out under vibration or the numerous and varied conditions common to motor, rail, air and Steamship transportation.' When removal of the closure plug is desired an exact opposite reaction occurs thereby affording easy removal therefrom. As the closure plug I0 enters the orice 30 more and more, the resistance to such entry increases gradually until ultimately the plug seat 22 rests rmly upon the and yieldability is thus afforded to this entering upper surfaces 34 adjacent the orifice 30. This increasing resistence to the entry of the closure plug I U is, of course. a direct result of the taperplug I@ in the orifice. When this pressure is released, the `bottom wall I2 will resiliently attempt to spring back into lits normal position. As a result, the closure plug firmly grips the internal walls of the orifice in a side sealing effect and the plug seat adheres to the surfaces adjacent the orifice in a top sealing effect whereby the closure plug tenaciously resists any efforts to remove the same due to mishandling of the equipment or due to the'jolting and jouncing inherent in transit. Such gripping action is aided to a great extent by the suction exerted by the closure plug in'such an orifice. When it is desired to remove the closure plug, it may be gripped by the removing tab and pulled upwardly out of the oriiice. If necessary, the closure plug I3 may have its annular flange 2li urged slightly 'inwardly whereby j the suction or vacuumeffect is destroyed and the 'Y cular top or upper wall Mlhas replaced the bottom wall I2 of the species shown in Figures 1 and 2. It is to be immediately observed that the lowerincst portion of the plug IUT which enters the orifice first is open with a cored-out recess directly facing into the orice. Greater flexibility portionwhereby a smoother and easier entry is possible. Sidewalls Id with tapering fins iii and an upper radially projecting annular flange 20 s with a plug seat 22' are similarly provided, along with a removing tab 28' on the top surface of the upper wallll.

When the plug Ill is inserted in its port or opening, the fins Iii' readily and resiliently yield and form a tenaciousside seal, as described above in connectionwithrplug itl. Similarly, the plug seat 22' effects van adhering top seal which is moistureand vaporproof and which will remain in sealing position until desired to be removed.

The closure plug may be made of any rubber or rubber-like material, either synthetic or natural or a mixture of both, depending on the specific requirements of the particular situation. It is essential that the material be sufciently flexible that the walls and surfaces thereof yield to the contours of. the openings in which they are to be placed. For use with engines or similar equipment,-such as for breather openings, exhaust ports,rtubes or similar orices, wherein contact with preserving compounds, oils or fuels is to be expected, it is necessary that the material be resistant to such chemical action. Additionally, the vmaterial should have sufficient hardness to maintain its configuration during its sealing action. A Shore hardness of 40 to 50 has been found to be acceptable in the majority of cases but such may be varied depending upon the cir-` cumstances. For themajority of situations, a synthetic rubber is,9f c curs e, preferred as its properties and characteristics lend themselves more readily to such requirements.

While I have shown and described what I believe to be a preferred embodiment of my invention in the matter of simplicity and durability of construction, ease of operation and use, etc., it will be obvious that the details of such construc tion may be more or less modified within the scope of the appended claims without departure from the principles of construction or material sacrice of the advantages of the preferred design.

I claim:

1. A hollow, resilient closure plug having a frustro conical form and providing a tapered body consisting of a resilient annular wall tapering throughout its axial length and dening a cavity, said cavity extending axially from the Wide end of said tapered body and terminating in a substantially flat, resilient closure Wall at the narrow end of said body, said closure Wall having a pull tab extending therefrom, said pull tab being positioned wholly within said cavity, there, further, being a radially outwardly extending, resilient, annular flange at vthe Wide end of said body, said annular Wall being provided adjacent the narrow end of said body with a plurality of annular fins, each of said fins, having a crosssectional shape of the form of an isosceles triangle with the base thereof being adjacent said annular wall, with the perpendicular bisector thereof being perpendicular to said annular Wall, and With the peripheral edges of said iins conforming to the taper or" said body.

2. A hollow, resilient closure plug having a frustro conical form and providing a tapered body consisting of a resilient annular Wall tapering throughout its axial length and deiining a cavity, said annular Wall being substantially uniform in thickness, said cavity extending axially from the Wide end of said tapered body and terminating in a substantially flat, resilient closure Wall, integral with said annular Wall, at the narrow end of said body, there being a radially outwardly extending, resilient, annular iiange at the Wide end of said body, said annular Wall having a plurality of tapering, resilient, annular iins integral with and projecting radially outward from that portion of said annular wall which is adjacent the narrowend of said `cody, said iins being similar to one another and each having the cross-sectional shape of an isos'celes triangle with the base of the triangle being adjacent said annular wall and with the peripheral edges of said iins conforming to the taper of said body.

CHANDLER. P. YARNALL.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 424,690 Rossman Apr. l, 1890 427,677 Finch May 13, 1890 560,227 McKenzie et al. May 19, 1896 1,120,369 Booraem et al. Dec. 8, 1914 1,710,363 Kramer Apr. 23, 1929 1,946,981 Lower Feb. 13, 1934 2,173,843 Hothersall Sept. 26,' 1939 2,196,785 Takiguchi Apr. 9, 1940 2,265,615 Stalter Dec. 9, 1941 2,487,635 Carpenter Nov. 8, 1949 

